Name
- Oburn, George1
- Ordnance Survey Office1
- Ormsby, —1
- Osborne, Henry, surveyor1
- Page, —, fl 17th cent1
- Parker, John, surveyor1
- Pearson, Karl, FRS1
- Petty, Frances, actress, daughter of Sir W Petty1
- Petty, William, 2nd Earl of Shelburne, 1st Marquess of Lansdowne, formerly Fitzmaurice, 1737-18051
- Petty,, Mary, née Williams wife of Charles 2nd Baron Shelburne1
- Pibourne, Christopher1
- Pighils, Richard, surveyor al Pighills1
- Pilkington, John1
- Plunkett, Nicholas1
- Plunkett, Patrick, 9th Baron Dunsany, politician, ?1594-?16691
- Pollexfen, Henry, Chief Justice of Common Pleas1
- Pooley, Nevil1
- Pope, Walter, MD, astronomer1
- Public Record Office, Dublin1
- Purdon, George, Captain1